Use for cutting and squaring. Right and left hand numbering and angle system. Diagonal line for triangle cuts. Extra 1⁄2 Inch on two sides for seam allowance. Great for miniatures and colourwash and for cutting and squaring blocks up to 31⁄2″. For use with rotary cutters & straight edge blades. Transparent, neon green double-sight lines that seem to glow on both light and dark fabrics.. Non-slip backing.